Improvement in grate-bars



NiTED STATES PATENT Critica,

IMPROVEMENT IN GRATE-BARS.

Specification forming part of Letters Patent No. 36,053, dated August 5, 1862.

To @ZZ whom it may concern:

Be it known that I, PHILIP GRIFFITH, of Philadelphia, Pennsylvania, have invented an Improvement in Grate-Bars; and I do hereby declare the following to 'be a full, clear, and exact description of the same, reference bei-ng had to the accompanying drawings, and to the letters of reference marked thereon.

My invention consists of a series of bars, each bar having a dovetailed recess forthe reception of a dovetailed projection on the adja- ,cent bar, in combination with a block or key, thewhole being arranged as described hereinafter, so that the bars may always retain their proper form and position laterally, and so that one or more bars may be readily removed or replaced without disturbing the adjacent bars.

In order to enable others to make and use my invention, I will now proceed to describe its construction and operation.

On reference to the accompanying drawings, which form a part of this specification, Figure lis a side viewof myimproved grate-bar with the supports' in section; Fig. 2, a plan View; Fig. 3, the same, showing the manner of removing one of the bars; Fig. 4, atrans verse section of the bars.

Similar letters refer to similar parts throughout the several views.

A A are the bars, the front ends of which rest on a plate, B, built into the sides of the furnace, the opposite ends of the bars resting on the plate D, secured to the rear of the furnace. On one side of each bar areformed four or any other convenient number of dovetailed projections, m, situated at equal distances apart from each other, and on the opposite side of each bar are formed dovetailed recesses, corresponding as regards size and position with the dovetailed projections.

Between the end a of the furnace and the rear ends of the bars, and resting on the plate l), is a block, E, of the same height as the end of the bars, the block being somewhat narrower than the space in which it fits, so as to allow for the necessary expansion of the bars when the latter become heated.

When the bars are iu their proper position in the furnace, the dovetailed projections of one bar fit snugly but freely in the dovetailed recesses formed in the adjacent bars, so that one bar cannot possibly rise above the other when the excessive heat has a tendency to warp the whofe set of bars. The most important object attained by the dovetailed projections and recesses, however, is the prevention of the lateral warping of the bars and the Widening of the spaces between them-a result which takes place with bars as hitherto constructed, owing to sudden expansion and contraction.

The importance of maintaining the bars at a uniform distance apart from each other is too well known to engineers to need explanation.

When one or more of the bars has to be removed, the block or key E must be withdrawn, when a longitudinal movement is imparted to the bar to be removed, (see Fig. 3,) the dovetailed projections thereby passing from the dovetailed recesses, after which the bar may be elevated or depressed at one end, Withdrawn from the furnace, and replaced therein without disturbing the adjacent' bars.

I am aware that bars have been heretofore constructed with projections on one side and recesses on the opposite side for the purpose of maintaining .the upper surface of a set of bars at a uniform level. This I do not claim; but

I claim as my invention and desire to secure by Letters Patent-V A series of bars, A, each bar havingadovetailed recess for the reception of a dovetailed projection on the adjacent bar, in combination with the block or key E, the Whole being arranged substantially as set' forth, for the purpose specified.

In testimony whereof Ihave signed my name to this specification in the presence of two subscribing witnesses.

PHILIP GRIFFITH.

Witnesses:

J oHN WHITE, CHARLES HoWsoN. 

